Map Reading 



U. S. Infantry Association 



Map Reading 

Jrom 

THE INFANTRY JOURNAL 



Copyright 1920 



Price 60 cents per copy 



The United States Infantry Association 
Washington, D. C. 



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TOPOGRAPHICAL MAP 

GETTYSBURG — ANTETAM 

Knoxun 



9 £rr^mfaf^.'9 5^a 





Scale:12 Inches -1 Mile 



I Mil. 



Scale of S lopes 

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Contour Interval 5 Feet. Dotum Mean Sea Level. 

Publi.hrJ by llir UniitJ S(,(„ In<»n(r.v Ai.oci.linrx 




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Map Reading 

Gettysburg War Game Map, Sheet P-11 



Q. What is a military map? 

A. A military map is one which shows the rela- 
tive distance, direction and elevation of ' 
all objects of military importance in the 
area represented. 

Q. What is map reading? 

A. The ability to grasp the general featiires of 
the map and to form a clear mental pic- 
ture of the ground represented by it. 

Q. What are the essential elements of map 
reading? 

A. 1. The conversion of map distances into 
corresponding ground distances: that 
is, an appreciation of the scale of a map. 

2. An appreciation of compass direction. 

3. A knowledge of the conventional signs 
and symbols employed by map makers 
to represent the various topographical 
features of the country included in the 
map. 

4. A knowledge of contours and what they 
are intended to represent. 

Note. — The map used in this conference on 
map reading is Sheet P-11 of the Emmittsburg 
quadrangle of the Gettysburg War Game Map 
prepared at the Army Service Schools, Fort 
Leavenworth, Kansas. 

SCALES 

Q. What is the scale of the map? 

A. Twelve inches equal one mile. 

Q. What do you understand by the statement 
"12 inches equal one mile?" 

A. That 12 inches measured in any direction on 
the map represents one corresponding 
mile on the ground; that any 6 inches 
measixred on the map represents }4 
mile on the ground. In other words, 
the scale of a map is the ratio between 
two points on the map and the corre- 
sponding points on the ground. 

Q. In what -ways may the scale of a map be ex- 
pressed? 

A. 1. By a plain statement in words and figures 
as given in the previous answer: "12 
inches equal 1 mile." 
2. Graphically, that is, by drawing a line on 
the map, dividing it into equal parts and 
marking them, not with their actual 
lengths, but with the map distance that 
they represent. 



3. By a Representative Fraction, con- 
tracted in practice to R. F. 
Q, You note that the R. F. for our map is not 

stated. What is it? 
A. The R. F. of our map is 1/5280. For con- 
venience expressed R. F. 1:5280. 
Q. How do you arrive at this conclusion? 
A. A R. F. is a fraction reduced to unity 'in 
which the numerator represents the map 
distance and the denominator repre- 
sents the ground distance both in the 
same unit of measure. We know that 
otir map is 12 inches to 1 mile. We make 
a fraction thus: 

Map Distance 12 inches 
Ground Distance 1 mile 
12 inches 1 

63,360 inches 5280 

This means that any one imit of measure 
on the map will represent 5,280 of the 
like imits on the ground. To prove this 
we have 12 inches or one foot on the map 
represents one mile or 5,280 feet on the 
ground. 

Q. What scales are prescribed by the War De- 
partment in making military maps and 
sketches. 

A. 1. For maps on which the organization of 
defensive positions are shown: 12 inches 
to 1 nule. Our war game maps are made 
on this scale. 

2. For position maps, place and outpost 
sketches, 6 inches to 1 mile. 

3. For road maps and sketches, 3 inches to 

1 rnUe. 

4. For strategic maps, 1 inch to 1 mile. 
Note. — Our Geological Survey maps are 

drawn on R. F. 1: 62,500, which is nearly 1 inch 

to 1 mile. To be exactly 1 inch to 1 mile 

they would have an R. F. of 1 : 63,360. 

Q. What are the two classes of map scales? 

A. 1. Working scales. 
2. Reading scales. 

Q. What is a working scale? 

A. The scale used by the topographer in making 
the map, as paces, strides, feet, lengths 
of a chain or rope, revolutions of a wheel, 
etc. 

Q. What is a reading scale? 

A. A reading scale is one used in laying off dis- 



Map Reading 



tances on the map. It is in a standard 
unit of measure with which we are famil- 
iar, such as miles, yards, feet, etc. 
Note. — In some cases the working and read- 
ing scales may be identical, as when the 
topographer measures his distances on the 
ground in yards and our reading scale is also in 
yards. 

Q. Suppose you have a map that has no graphi- 
cal scale line on it but has an R. F. or a 
statement that so many inches equal one 
mile. How would you go about measuring 
distances between points on the map? 
A. It wotdd be necessary to construct a graph- 
ical scale. 
Note. — ]Modem maps usually have a graphi- 
cal scale on them. Should they not, it is a very 
simple matter to solve a scale problem and con- 
struct a scale provided you have the R. F. or 
data from which you can deduce it. With the 
following simple formula any scale problem may 
be solved. 

Let m = the number of units of measure to 
be represented by the scale Une. 
In hnear scales make this always 
even 1,000 or 2,000, so there is 
nothing further to remember. 
Let /) = the number of inches in the unit of 
measure. For a scale of yards p 
would be 36, for a scale of 30-inch 
paces p would be 30, for a scale of 
meters p would be 39.37. 
Let n=the denominator of the represen- 
tative fraction. For 12 inches to 
the mile n wovild be 5,280. 
Let jc=the number of inches in the scale 
line to represent m tmits of 
measure. 

Then:-:^^H?^^^„;c. 
n 

Or, if you prefer a nile, the following is appli- 
cable: Mtdtiply the number of vmits of 
measure in the scale line by the ntunber 
of inches in the vmit of measure and 
divide by the denominator of the R. F. 



The quotient will be the number of 
inches in the scale Une. Applying the 
formula, let us work out the scale of 
yards for our map. 

m = 1,000 yards, the number of units of 
measure to be represented by the 
scale line. 
/) = 36 inches, the number of inches in 

the unit of measure. 
n = 5,280, the denominator of the R. F. 

Then m times p, divided by n = x. 
x: = 6.81, the number of inches in the 
scale line to represent 1,000 yards. 
Draw a line 6.81 inches long. Divide it 
into five equal parts, each representing 
200 yards. Divide the left division into 
two equal parts, each representing 100 
yards. You have yotu- scale ready for 
use. 
Example. — You have determined your pace 
to be 30 inches, your stride is therefore 60 
inches. Construct a scale of strides, 3 inches 
to 1 mile. 

m= 1,000 strides. That is, the scale, 
when completed, will represent 
1,000 strides. 
^ = 60 inches. 
w = 21,120, the denominator of the R. F. 

3 inches = 1 mile, 
a; = length of the scale line in inches. 
Then: 1,000 times 60, divided by 
2 1 , 1 2 = 2 . 84 inches. Therefore a 
line 2.84 inches long will represent 
1,000 strides on a scale of 3 inches 
= 1 mile. 
Construction. — Draw a line 2.84 inches 
long. Divide it into five equal parts. Each 
part will represent 200 strides. Divide the 
left-hand part into eight equal parts. Each 
part will represent 25 strides. You have a 
scale of strides of 60 inches at 3 inches to 1 
mile, complete and ready for use. 

The method of dividing the line into equal 
parts is shown in Fig. 1. 



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Fig. 1. 



Map Reading 



The line A — B is 2.84 inches long. We 
want to divide it into five equal parts. Draw 
the line A — C at any convenient angle to A — B, 
and of a suitable length. On the line A — C 
lay off five equal spaces from A. Now, draw 
a line from the fifth point on A — C to B. 
Draw lines parallel to this line through the other 
four points on A — C and extend them up- 
ward untU they cut the line A — B. This 
process also divides A — B into five equal parts. 
Each of these parts will represent 200 strides. 

In a similar manner divide the left-hand 
division into eight equal parts as shown in the 
illustration. 

Now, erase all the lines except the finished 
line A — B and you have the complete working 
scale as shown in Fig. 2. 

Zoo o zoo 

■ I 



Q. What is the distance from road fork 443 to 
road fork 395, via 428. 

A. 2,775 yards. 

Q. You have two machine guns on top of hill 
462. You observe a mounted patrol on 
the unimproved road at the farmhouses 
at A. You decide to open fire. What 
range would you give your gunners? 

A. Range, 960 yards. 

Q. You are in command of a combat patrol of 
one squad. You have arrived on the hill 
at B southeast of the Clagett farmhouses. 
You observe a small body of the enemy 
engaged in the destruction of the railroad 
bridge at C. You decide to open fire. 
What range would you give? 

A. Range, 600 yards. 



1 I nJ, 



400 



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Fig. 2. 



Q. How do you determine the distance between two 
points on the map? 

A. 1. By measuring along the edge of a piece of 
paper the distance between the two 
points and applying that distance to the 
graphic scale on the map, and reading 
directly from it. 

2. To measure the distance from one point 
to another along a winding road or 
course place the edge of the paper along 
each straight stretch, placing the point 
of a pencil or pin at the edge of the paper 
at each such successive point where the 
direction changes and shift the edge of 
the paper around to follow the courses 
until the total distance has been covered. 
Apply this total distance to the scale of 
the map and read direct. 

3. The distance may be measured by a pair 
of dividers as follows: Place leg No. 1 of 
the dividers at the initial point; spread 
leg 2 out to the first change of direction; 
holding leg 2 in place, swing leg 1 
around vrntU a line between the points of 
the two legs is in prolongation of the 
next course ; then holding leg 1 in place, 
spread leg 2 out to cover the course. 
You thus have your first and second 
stretches of the distance accurately 
laid oflE between the points of your 
dividers. Continue this process until the 
entire course is covered; apply the dis- 
tance to the graphic scale on your map 
and read direct. 



Q. Your platoon is marching via the 443-415- 
428-395-383 road. It has halted for the 
regular hourly rest at the road fork 443. 
It is now 9 a. m. You continue the 
march. At what time will you reach road 
fork 383? 

A. The distance is 3,580 yards. Marching 
at the rate of 80 yards per minute the 
platoon will march 45 minutes, and will 
reach road fork 383 at 9.45 a. m. 

DIRECTION 

Q. How is the north point of a map indicated? 

A. By a line placed on the map at a convenient 
place with an arrow pointing to the 
north. 

Q. On our map there is no line showing the 
north. How would you determine which 
is north? 

A. When we get a map with no north line on it 
we can usually safely assume that the 
reading on the map runs east and west. 
This makes the sides of the map as we 
look at it nm north and south. The top 
is north, the right-hand side east, the 
left-hand side west, and the bottom 
south. This is exactly the case with the 
map on which this conference is based. 

Q. How is the direction of one point from another 
stated in military map reading? 

A. By the points of the compass. One point is 
said to be north, east, south or west from 
another point. When it lies between 
the north and east points it is said to be 



Map Readincc 



north (so many degrees) east; when 
between the east and south it is said to 
be south (so many degrees) east; when 
between the south and west it is said to 
be south (so many degrees) west, and 
when it is between the west and north it 
is said to be north (so many degrees) 
west. 
Q. What is the direction of 395 from 428? 
A. It is east. 

Q. What is the direction of 383 from 443? 
A. It is north 45 degrees east. 
Q. What is the direction of road fork 443 from 

415? 
A. It is south 20 degrees east. 
Q. What is the direction of 427 from road fork 

443? 
A. It is west. 

Q. What do you understand by orienting a map? 
A. Placing the map in such position that every 
road, stream, or other feature on the 
map will be parallel to its actual position 
on the ground; in other words, to make 
the map and the ground it represents 
coincide. ^ 

Q. What are the objects of orienting the map? 
A. To enable you to pick out and identify on 
the grotmd all the features shown on 
the map. 
Q. By what methods may a map be oriented? 
A. 1. When the map has a magnetic meridian 
on it: Place the north and south Une of 
compass parallel to the magnetic merid- 
ian and turn the map vmtil the north 
end of the needle points to the north of 
the circle. If the true meridian only is 
shown on the map, you must know the 
declination and make allowance for it. 
If the declination is not more than 4 or 
5 degrees, the orientation on the true 
meridian or along the up and down bor- 
ders of the map will be sufficiently ac- 
curate for all practical purposes. 
2, When you have no compass or the meri- 
dian is not known on the map : (a) If you 
can locate on the map your cosition on 
the ground and can identify another 
place on the map which you can see 
on the ground, shift the map around 
until the two points on the map are 
aligned on the distant point on the 
ground and you have the map oriented. 
(b) By reference to a straight road or Une 
of railway on which you may be 
standing, turn the map untU the con- 



ventional symbol points in the same 
direction as the feature that it repre- 
sents. In both of these methods the 
points used for orientation should be 
as far apart as possible, and in any 
case they should be more than an inch 
apart on the map. 
Q. Ho-w itould you locate your position on the 

map? 
A. 1. When the map has been oriented by com- 
pass. Sight along the ruler at an object 
on the ground, at the same time keeping 
the ruler on the plotted position of this 
same object on the map. Draw a line 
towards yourself. Locate another point 
on the ground that is plotted on the map 
and repeat the process. The intersection 
of these two lines is your map position. 
These lines should form an angle of not 
less than 30 degrees and not more than 
150 degrees. Get the angle as nearly 90 
degrees as practicable. 
2. If the map has been oriented by means of 
a straight line drawn between two map 
points, it will be necessary to draw but 
one line from an object on the ground, 
and the intersection of this line with the 
line already on the map will be your 
location on the map. 
Q. Suppose you are at the railroad bridge at C. 

How would you orient your map? 
A. Turn the map so that the railroad runs in 
prolongation of the line on the map that 
represents it, and your map is oriented. 
Q. You are standing on hill 462 where there is no 
well-defined feature on which to orient 
your map. You have a box compass. 
How would you orient? 
A. Lay the compass on the map with its box 
edge parallel to the sides of the map — 
the 0-360 point towards the top of the 
map. Now turn the map until the com- 
pass needle reads zero, and your map is 
oriented. 
Q. You are out in the open fields on the high 
ground about 900 yards east of the Clagett 
farm. You have a compass. You want 
to get your location on the map approxi- 
mately accurate. How would you go 
about it? 
A. First orient yotu- map with the compass as 
explained above. Now lay a ruler on 
the map, pivot it on the Clagett house 
on the map, and sight it at the Clagett 
house on the ground. Draw a line 



Map Reading 



towards yourself. You are on this Line 
somewhere. Now go around to the top 
side of the map and in like manner pivot 
your ruler on the map location of the 
farmhouse at C and point it at the 
farmhouse on the ground. Draw a line 
towards yourself. Your position is also 
on this line somewhere. At the inter- 
section of the two lines is your posi- 
tion. This process is technically called 
"resection." 

Q. You are traversing {walking) along the road 
395-428, you see a point on the high 
ground to the south that you want to locate 
on your map without going over there. 
How would you do it? 

A. At 395 orient your map. Pivot your ruler at 
395 and sight it on the distant point. 
Draw a line. The point must be on this 
line somewhere. When you get to 428 
repeat the process, that is, orient your 
map, pivot your ruler on 428 and sight 
on the distant point. Draw a line. The 
point must also be on this line. Where 
the two lines intersect is the location of 
the distant point on the map. This is 
what is technically known as "inter- 
section." 

CONVENTIONAL SIGNS 

Q. How are the topographical features of the 

country included in a map shown? 
A. By means of conventional signs that all per- 
sons essaying to use the map should 
be familiar with. 
Q. What is the characteristic of these conven- 
tional signs? 
A. They are drawn as nearly as practicable to 
resemble the features on the ground that 
they represent. 
Note. — The conventional signs are the A, B, 
C's of map reading. You must be absolutely 
familiar with them if you would read a map. 
One of the best methods of learning them is to 
practice making them at odd moments until 
you are familiar with all of them. 

The following illustrations (Fig. 3) show the 
system of conventional signs employed in mak- 
ing the Gettysburg war game maps and their 
3 inches to 1 mile reproductions. Study and 
practice them until you learn them thoroughly. 
Q. Locate an improved road. 
A. The 395-428 road. 
Q. Locate an unimproved road. 
A. The road leading to the southwest from 415. 



ffflproved Roads 
tJrilmp roved Roads 
Trmis 

Roftroads.Single Track 
»» Double Track 
♦♦ Urban or Suburban 
Fences, Bar bed Wire 

'» Smooth.** 

>' Worm 

»' S tone 

M Hedge 
Streams under 15'w.de 

T> Over »» " 
Embonkment 
Cutting 
Arroyo or Ditch 

Builcftngs 
Bridges 
S+one Culver ■^s 



11111(1 
I I I I I I I 



Corn 



Cultivated Lond 



Trees without Underbrush 



Woods with Underbrush 



Brush 



Pine. Trees and RocUs 



Orchard 



Marsh 



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AM-- 






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Fig. 3. 



Q. Locate a single railroad. 

A. That paralleling the 443-415-428 road. 

Q. Locate a barbed-wire fence. 



Map Reading 



A. Fence paralleling railroad and to east of it, 

Q. Locate a smooth-wire fence. 

A. The fence along almost any road on the map. 

Q. Locate a stream under 15 feet mde. 

A. That running east and west through the 
north central part of the map. 

Q. Locate a stream over 15 feet wide. 

A. In the southeast comer of the map. 

Q. Locate embankments and cuts. 

A. See those along the railroad. 

Q. Locate a bridge. 

A. That at C on the railroad. 

Q. Locate houses and barns. 

A. The Clagett farm south of 415. 

Q. Locate corn land. 

A. The big field northwest of the Clagett farm- 
houses. 

Q. Locate cultivated land. 

A. North and south of hill 462 . 

Q. Locate forest land. 

A. Along the west slope of the valley nonning 
south from 383. 

Q. Locate an orchard. 

A. East of road fork 428. 

CONTOURS 

Q. What are contours? 

A. They are lines of equal elevation. Lines cut 
from the siuf ace of the earth by imagi- 
nary horizontal planes at an equal verti- 
cal distance from each other. 

Q. What do contours show? 

A. 1. The relative elevation of all points on the 
map. 

2. The slope of the ground between any two 

points on the map. 

3. The shape and form of the ground in- 

cluded in the area covered by the map. 
Q. What are the principal characteristics of 
contours? 

1. All contotus either join or both ends ex- 
tend to the edge of the map. When they 
join they either represent a hill top or a 
depression — a hill when the smallest 
closed contour is higher than the next 
one to it and a depression when it is 
lower. 

2. Where the contours are equally spaced 

the slope is tmiform. Where they are 
close together the ground is steep, and 
where they are wide apart the slope is 
gradual. 

3. A watershed is the high ground between 
two water courses. The water flows 
away from it on both sides and is indi- 



cated by the higher contours bulging out 
towards the lower ones. 
4. A water course is the low ground between 
two watersheds. The drainage from 
both sides of it joins in one stream and 
is indicated by the contours bending 
sharply towards the higher ones. 
5. A sadle or ool is the space between the 
summits of two adjacent hUls. It is indi- 
cated by two contours of greater eleva- 
tion on two sides of it and two of lesser 
elevation on the other two sides. 
6. A spur is an under feature that projects 
out from one of the main topographioal 
features. 

Q. You see at the bottom of the map a statement 
"Scale of Slopes," and underneath it a 
line divided up into parts and each part 
marked 1°, 2°, 3', etc. What do you un- 
derstand this means? 

A. This is what is technically called a scale of 
"Horizontal Equivalents." It is used 
in map making to locate contour points 
on the map and is used in map reading 
to determine the slope of the ground at 
any point. We know that the ground 
will rise 1 foot on a one-degree slope in 
57.3 feet, and that it will rise 5 feet in 
5 times 57.3, or 286.5 feet. We simply 
measure off 286.5 feet or 95.5 yards, 
and that is the H. E. for 1 degree. 
Test this by measuring off the scale of 
slope for 1 degree and apply it to the 
graphical scale on the map, and you 
will find that it measured 95.5 yards. 
Now to find the H. E. for the other 
degrees we simply divide the 95.5 by 
the numbers 2, 3, 4, etc., and lay off 
the quotient on the scale of slopes. 

Q, Just below the scale of slopes we have the 
statement " Contour interval 5 feet." 
What do you understand by that? 

A. It means that the vertical distance between 
contours on the map is 5 feet. That 
if the contours were marked on the 
ground one would be 5 feet vertically 
above the other. 

Q. You also see the statement "Datum mean 
sea level." What does this mean? 

A. That all the points on the map are so 
many feet above the level of the sea. 
It means that hill 462 is 462 feet above 
the mean level of the Atlantic Ocean. 

Q. Locate a watershed on the map. 

A. The ridge rimning north and south near 
the eastern edge of the map. The 



Map Reading 



9 



farmhouses at A are on the top of the 
watershed. Trace out the 445-foot 
contour on this watershed and see how 
it runs. 

Q. Locate a water course. 

A. The stream running across the map from 
south to north through the east central 
part of the map. Trace it out and see 
the watersheds that it Ues between. 

Q. Where is the steepest ground on the map? 

A. On the wooded slopes of the watershed to 
the east of farmhouses at A. 

Q. Where is the most generally gently sloping 
ground on the map? 

A. In the cultivated fields in the northwest 
comer of the map. 

Q. Trace out the ^0-foot contour and see how 
it runs on the map. 

A, We note that the 440-contour comes on the 
map at the southeast comer, nms 
north to the end of the watershed, then 
doubles back along the west side of 
the watershed, winds its way to the 



north of hill 462 and then towards the 
northwest, where it leaves the map. 
It comes on the map again at the western 
edge north of hill 443, comes by Clagett 
farm, runs by road fork 443, thence 
south, and leaves the map at the south 
edge just west of the railroad. Again, 
small portions of it come on and leave 
the map at the north edge. 

Q. Can you see road fork 415 from road fork 443? 

A. No. The high groimd southeast of the 
Clagett farmhouses intercepts the line 
of sight. 

Q. Can you see road fork 383 from hill 462? 

A. Yes. There is no higher groimd lying 
between the two points. 

Q. Can you see the Clagett farmhouses from the 
farmhouses at A ? 

A. Yes. 

Q. When there is doubt regarding the visibility 
of one point from another how can you 
determine the matter definitely? 

A. By making a profile along the line of sight. 



MILITARV AliP TOPOGEAPhlCAL TCBMS- 



RIGHT BANK. 

LEFT BANK. 

8UOPF0«CUPP. 

HOLLOW OR VALUEV. 
STeEPSLOP£. 
PEAK. 



GENTLE SUOPE. 

MILITARY CRC6T. 

CREST CTOPOGCAPniCAL) 
ROAD t=ORK 

SUNKEN ROAD- 



RlOGE. 

RIO.OE ROAO. 

RIOGE CREST. 

H9RIZON OR SKYLINfi. 
CLEARIMO. 

ROAO CENTER. 




Fig. 4. 



10 



Map Reading 



This is made by plotting to scale on a 
piece of profile or cross-section paper: 
(a) The point from which the observa- 
tion is made, (b) the point to be ob- 
served, and (c) any point that may 
intercept the line of sight. 
Draw a line from (a) to (b), the platted 
points. If it touches (c) the points are 
not intervisible. If it does not touch 
(c) they are visible one from the other. 
Note: Fig. 5 shows the method of construct- 
ing a profile along the line (a) — (b) on the map 
with point (c) intercepting. The point (b) 
is not visible from (a). Get some cross-section 
paper at a stationery store and plot several 
profile lines as given on the map (d) to (e) 
and (f) to (g). Note that where the contours 
are close together on the map the line on the 
profile is very steep and that where the con- 
curs are far apart on the map the profile 
line is not so steep. By a careful study of 
profile lines you can gain much knowledge of 
contours and what they represent. 
Q. Where would you post a sentinel on hill 462 
to get the most extended view to the north? 
A. At the north point of the hill just west of 

(c). 
Q. What is the slope of the ground between 

X and y? 
A. One degree. Apply the scale of slopes 
between adjacent contours and you 
can determine the slope at any point 
on the map. The shape of the con- 
tours will give you the conformation of 
the ground at any point. 

Practical Problems in Map Reading 
Map: P- 11— Section Emmitsbtirg Map 

Note. — In the solution of the following ten 
problems disregard the scale and vertical 
interval of the map. 

scales 

Q. The range from the Clagett farmhouse to the 
railroad culvert at C is 1,000 yards. 
Construct a scale of yards for the map. 
What is the R. F.? 

Q. How long will it take a company to march 
from the ham at A to road fork 443, via 
383 and 428, marching at the rate of 88 
yards per minute and making the regular 
halls? The R. F. of the map is 1: 21,120. 

Q. The map is 4 inches to one mile. What is 
the distance as a crow flies from the 
barn at A to the following points: Cross- 



roads 443; Point (a); the Clagett farm- 
house; road fork 428 ? 

Q. A cyclist moving at the rate of 12 miles per 
hour travels from road fork 443 to road 
fork 415 in 9 y^ minutes. Construct a scale 
of yards for the map. 

Q. Sound travels at the rate of 1,100 feet per 
second. How soon afterwards would the 
report of a rifle fired at road fork 395 be 
heard at (a) and road fork 427 respectively? 
R. F. of map is 1 : 5,000. 

Q. The R. F. of the map is 1:20,000. The 
stream running east and west across the 
north central part of the map flows at the 
rate of 2 miles per hour. How long will 
it take a plank to drift from the railroad 
culvert at c to the bridge just north of 383? 

Q. Companies of infantry bivouacked at A and 
road fork 427, respectively, are ordered to 
rendezvous at road fork 428 at 11.45 a. m. 
At what time will they have to start march- 
ing? The scale of the map is 3 inches to 
1 mile. 

Q. What is the distance in meters from 383 to 
427 via the 395-428-415 road? Scale of 
map is 6 inches to 1 mile. A meter is 
39.37 inches. 

Q. If the distance from (/) to (g) is 1,000 meters 
construct a scale of yards for the map. 

Q. The map is 12 inches to 1 mile. In pacing 
from 395 to 428 you take 1,118 paces; 
from (e) to (d) you take 1,350 paces; via 
the main road from 427 to 443 you take 
1,230 paces; from 443 across country to 
the barn at A you take 1,400 paces. 
What is the length of your pace? 

direction 

Q. Let us say the line {d)—{e) is magnetic north 
and south. What is the compass bearing 
of the following points from road fork 
443: the barn a/ ^; 383; 415; Hill 462; 
427; Hill 443? {Note: Draw a line 
through 443 parallel to the line {d)-{e). 
Draw radiating line from road fork 443 
to the points indicated. Apply the pro- 
tractor and read the bearings direct.) 
(Cut out the protractor on the sheet of 
cardboard for solving these problems.) 

Q. The side borders of the map run magnetic 
north and south. A scout marching at 
the rate of 80 yards per minute leaves the 
barn at A, proceeds on a bearing of 260° 
for 9 minutes; thence 350° for 7 minutes; 
thence 300° for 5 minutes; thence ^0° for 



Map Reading 



11 




n 



Map Reading 



9 minutes. Locate his position on the 
map. What is the bearing from this 
point back to the point of starting {the 
barn at A)? 

Q. The side borders of the map run true north 
and south. The declination is 7 west. 
A scout starting from road fork 427 
marcheso7tacompassbearing38 . At what 
point will he leave the map? 

Q. The side borders of the map run true north 
and south. The declination is 7° west. 
A battalion is in approach march forma- 
tion with the first platoon of Company 
A as base platoon. The base squad of 
this platoon is at (c). The compass 
bearing of the directing line is 310°. 
At what point will the base squad cross 
the railroad? 

Q. An observer standing at (c) finds that the 
compass reading to road fork 395 is 80°. 
What is the true direction of the following 
points from (/) , assuming the declination 
to be 10° "West: the barn at A; road 
fork 443; road fork 427; road fork 428; 
the Clagett farmhouse; point {a) ? 

Q. The side borders of the map run true north 
and south. The declination is 4° west. 
Scale of map 12 inches to 1 mile. Two 
scouts start from (c); Scout A marches 
on a compass bearing of 40° for a distance 
of 1,400 yards; Scout B marches on 
a compass bearing of 320" for a distance 
of 1,200 yards. How far apart are the 
two scouts? What is the compass bearing 
of Scout A from Scout B? Can Scout 
A see Scout B? 

Q. The side borders of the map run true north 
and south. An observer at (g) takes a 
compass bearing on (c), which reads 
193°; what is the declination? Based 
on the declination thus determined, what 
is the compass bearing of 383 from 415? 

Q. The side borders of the map run true north 
and south. The declination is 8° east. 
A scout arrives at road fork 428 and 
decides to march directly on the barn at 
A. What is the compass bearing that he 
will march on? 

Q. The line {f)-{g) is magnetic north and south. 
Its declination is 7° west. A scout 
marches true south from 4:15 for a distance 
of 1000 yards; thence on a compass 
bearing of 100° for a distance of 1,200 
yards; thence on a compass bearing of 
37° for a distance of 800 yards. What 



compass bearing will he have to march 
on to get back to his starting point? 

Q. The side borders of the map are true north 
and south. An observer finds that the 
true bearing of 383 is 51° and 428 is 
308°. Show his position on the map. 

Q. The line {c)-{a) is magnetic east and west 
(a) to the east. A scout at the barn at A 
takes a compass bearing on a windmill 
which is 167°; on arriving at (c) he takes 
another compass bearing on the same 
point which is 88°. Locate the windmill 
on the map. 

Q. The side borders of the map are true north 
and south. The declination is 7° W. 
An observer at (a) reports an enemy 
machine-gun nest at a compass bearing 
of 345°. Another observer at (c) reports 
the same machine-gun nest at a compass 
bearing of 24°. What is the direction of 
the machine-gun nest from a battery of 
artillery at road fork 427? What is the 
range? Scale of map 6 inches to 1 mile. 

Q. The line {f)-{g) is magnetic north and south, 
ig) north. A compass bearing' to road 
fork 427 reads 165°; another compass 
bearing to the farmhouse north of hill 
443 reads 275°. Locate the point on the 
map from which these bearings were 
taken. 

Q. The side borders of the map run true north 
and south. The declination is 7° west. 
A scout is on the 443^15 road. He 
takes a compass bearing to (/) which 
reads 100°. Where is the scout on the road? 

CONTOURS 

Q, If the contour at (c) is 120 feet and that at 
(/) is 4:0 feet, what is the Vertical Interval? 

Q. If the contour at x is 640 state the elevation 
of the following points: Clagett farm- 
house; road fork 395; road fork 428; 
(a) ; (e) ; road fork 443 ; the barn at A . 

Q. Examine the line {d)-{e). Where is the gentlest 
and steepest slope on it? 

Q. Mark the heights of the contours on a line 
drawn from the Clagett farmhouse to 
the barn at A. The contour at (c) is 320. 
The Vertical Interval is 10 feet. 

Q. Suppose the heights of (g) and (/) to be 600 
and 760 respectively. What are the 
heights of the contours nearest the follow- 
ing points: 383; 428; 443; 462; 427? 

Q. An aviator is 800 feet above 383 and travel 



in a straight line south-west across the 
map. If he maintains the same level 
throughout the flight what is his height 
above the ground when he leaves the 
southwest corner of the map? The V. I. 
is 20 feet. 
Q. Mark the heights of all contours cut by a line 
from (e) to (c). (F. 7. 10 feet; the eleva- 
tion of (g) is 470.) 

Note. — In the following problems the scale of 

map is 12 inches to 1 mile. The V. I. is 5 feet. 

Q, State whether the following slopes are con- 
cave or convex: From the barn at A 
to the stream 250 yards to the west; from 
if) to the stream 700 yards to the north 
(sighting along the line (/)-(g)). 

Q. Could a man standing at (c) see others at 
the barn at A; at 427; at the Clagett 
farmhouse; at 415; at 383; at 395; 
at {a)? 

Q. Standing at (c) with the eye 5 ft. above the 
ground and looking at (/), where will the 
line of sight strike the ground? Standing 
at the barn at A with the eye 5 feet above 
the ground and looking at (/), where will 
the line of sight strike the ground? 

Q. A scout has reached (o) ; will he be able to see 
383; ^; (g); 415; the Clagett farmhouse; 
U3; 427; Hill 462? 

Q. What must be the height of a flag-staff at 
the Clagett house to be visible from the 
barn at A? 

Q. Where would you establish visual signal 
stations in order to communicate between 

427 and 383? 

Q. A scout is in the cupola of the barn at A, 
45 feet above the ground. He is watching 
the road leading towards 383. At what 
point on the road will a hostile patrol 
moving south come into view? 

Q. A scout is in a tree 15 feet above the ground 
at the southeast corner of the orchard east of 

428 observing the 428-383 road. At what 
points on this road would a hostile patrol 
marching west from 383 be visible? At 
what parts of the road would they be hidden 
from view? 

Q. When an aeroplane was over (d) the bridge 
at 383 was just visible. At what height 
•Was the plane flying above (d) ? 

Q. Could a patrol go from A to C without coming 
under the observation of a hostile scout 
at (c) ? Show the route. 

Q. Draw a line from (e) to (c) and make a 
cross-section. 



Map Reading 



13 



Q. Make a cross-section along the road 428- 
395. Show which slopes are convex and 
which are concave. 

CONVENTIONAL SIGNS 

Q. Draw a square 4 inches on a side and make 
a sketch map embracing the following 
features: 

a. A single track railroad running from 
west to east across the center. 

b. A telegraph line parallels the railroad 
on the north side. 

c. A stream crosses the map from southwest 
to northeast, flowing northeast. 

d. An improved road runs north and south 
across the map, crossing the stream and 
railroad east of the center of the map. 

e. An unimproved road runs east and 
west across the map one inch south of the 
railroad. Crosses stream at a ford. 

f. Two smaller streams running from the 
north and two from the south enter the 
main stream. One from each direction 
across the railroad. 

g. The elevation at the point where the main 
stream leaves the map is 500 feet. At 
the point where it enters the map {south- 
west corner) 535 feet. Fill in the 510, 
520, 530, 540 and 550 contours. The 
highest point on the map has an elevation 
of 555 feet. 

h. Show the cuts and fills along the railroad, 
i. The rectangle formed by the railroad, 
improved road north and east edge of 
map is covered with meadow land with 
trees scattered here and there and quite 
numerous along the stream. The rec- 
tangle to the south of that just described is 
wooded country. The triangle bounded 
by the main stream, the improved road 
and the unimproved road is covered with 
an orchard. A farmhouse with barn is at 
the crossroads. The rest of country to the 
south of the unimproved road is cultivated 
in corn and wheat. Fill in the remainder 
of the map with appropriate conventional 
signs of your own choosing, employing the 
signs for the various classes of fences, 
and vegetation covering the ground. 

Q. Practice drawing the conventional signs 
shown in Fig. 3. 

Q. Draw a sketch showing the water system of 
an area and fill in the contours to corre- 
spond thereto. 



14 



Map Reading 



Practical Problems in Map Reading 

Map: Emmitsburg Sheet 

scales 

Q. What is the scale of this map expressed in 
inches to the mile? 

Q. You want a scale of meters for this map. 
How would you go about getting it {a 
meter is 39.37 inches)? Try out the for- 
mula. 

Q, What is the distance from the road fork at 
Four Points to road fork 481 at Longs via 
the 365-405^68-481 road? 

Q. You have two machine guns on hill 442. 
{south 30 degrees west from Four Points), 
You have located an enemy detachment at 
Martin's Mill. You decide to open fire. 
What range do you give your gunners? 

Q. What is the distance from road fork 481 at 
Longs to Fair Play via Emmittsburg? 

Q. Your platoon is bivouacked at Four Points. 
It has been ordered to rendezvous at road 
fork 443 (on the Frederick Turnpike) at 
9.37 a. m. What time will you have to 
start your march? 

Q. Your company has been ordered to entrain at 
Emmittsburg at 10.47 a. m. You are 
required to be at the entraining point 30 
minutes before the time designated. You 
are bivouacked at Thomas Creek Church. 
All roads are available for your march. 
What time will you start marching? 

Q. Your platoon is marching south on the Fair- 
play-Emmittsburg-Longs road. You start 
from the cross roads at Fair play at 9.00. 
At what time will you pass road fork 488, 
road fork 422 (west of St. Joseph's Col- 
lege), cross-roads 466 {west of Matters)? 
Where will you make a halt? 

Q, A sketcher takes paces of 32.2 inches. Con- 
struct a working scale of paces at 6 
inches to one mile. 

Q. A sketcher is making a road map at 
a scale of 3 inches to 1 mile. He 
is measuring his distances by count- 
ing the revolutions of a AO-inch wheel. 
Construct a working scale. Construct a 
reading scale for this sketch to read yards. 

Q. Your platoon is at the bridge over the Mono- 
cacy near the Stull farm. It is now 9 
a. m. You are ordered to march via the 
383-^20-365-4:05-4:68-453-Emmitsburg- 
Fairplay road to Fair play. At what 
hour will you pass 468; and 488? Where 
will you make your regular hourly halts? 



Q. Your company {less one platoon) is at Fair- 
play. The detached platoon at road fork 
444. You are ordered to be at the rail- 
road station at Emmitsburg at 10.38 a. m. 
At what hour will each element of the 
company have to start its march. 

Q. How far will a man march in going from the 
bridge northwest of Stull farm to Matters via 
383-420-/"oMr Pot«/5-365^18-387 road? 

Q. The head of your column is now at the cross 
roads at Fairplay. It is ordered to be at 
cross-roads 446 west of Matters at9.27 a. m. 
What time will you have to start marching? 

Q. How long will it take a column to march from 
Fairplay to Matters by the shortest route? 

Q. It is known that the enemy has a battery of 
75s at road fork 428 {south of Matters). 
It has an effective range of 5,000 yards. 
You have a battalion of infantry on the 
Stull-4:52 road with the head of the 
column at the bridge over the Monocacy 
northwest of Stull. You are ordered to 
march to Emmitsburg. 

Q. Where would you place machine guns on 
the east of Four Points to cover the 
bridges over the Mill Run and Tom's 
Creek at Four Points? 

Q. You. have a French map that has a scale of 
meters on it. You lay off 2 inches on 
the scale and find that it reads 1,016 
meters. Construct a reading scale of 
yards for the map. 

Q. You have been ordered out to make a road 
sketch mounted. You have tested your 
horse and find that he travels at the rate 
of 5}4: miles per hour. The scale of 
your sketch is to be 3 inches to 1 mile. 
Construct a ivorking scale to read minutes 
and half minutes. 

Q. You take a pace of 33.4 inches. You have 
a map on which the legend and scale have 
been torn off. You pace the distance be- 
tween tivo points on the ground and find 
it to be 1,500 paces. You measure this 
corresponding distance on the map ajid 
find it to be 2^ inches. Construct a 
reading scale of yards for the map. 

DIRECTION 

Q. What is the direction one from the other of 
the folloiving points: Emmittsburg from 
Longs; Fairplay from Emmittsburg; Four 
Points from Longs; Matters from Four 
Points; Martin's Mill from Cumps Mill; 
St. Joseph College from Cumps Mill; St. 
Joseph's College from Four Points? 



Map Reading 



15 



Q. You are somewhere on the high open ground 
east of Longs. You have a compass. How 
would you go about locating your place so 
as to indicate it on your map? 

Q. You are reconnoitering along the road from 
Thomas Creek Church north to 449. You 
discover a machine-gun nest across Toms 
Creek in the edge of the woods east of hill 
469. How would you locate it definitely 
on a map to send hack with a message? 

Q. You are somewhere in the open field north 
of hill 487 {east of Longs). You have 
your map and compass. Explain how 
you would go about the task of locating 
your position accurately on the map. 

Q. Our line runs along the high ground 420- 
Thomas Creek Church-4A9-hill 466. We 
have observation stations at Thomas 
Creek Church and at 449. An enemy 
machine-gun nest has been discovered 
on hill 469. Explain how you would go 
about the task of platting its location 
accurately on the map. 

Q. What is the direction of the following points 
from the road fork at Matters: St. Mary's 
College; Fairplay; Stull; Clagett; Lime 
Kiln at road fork 462 ? 

Q. Describe the meanderings of Tom's Creek, 
using compass directions, from Cump's 
Mill to its mouth. 

Q. You are going across country from Longs 
to Cumps Mill. What is your compass 
reading? 

CONVENTIONAL SIGNS 

Q. Locate the following by conventional signs: 

1. Improved road bordered by smooth wire 
fence. 

2. Unimproved road. 

3. Railroad. Is it single or double track? 

4. Various classes of fences. 

5. Streams over 15 feet and under IS feet wide. 

6. Embankments, cuts and array os. 

7. Buildings. 

8. Bridges. 

9. Corn, cultivated land. 

10. Wooded country, 

11. Orchards. 

Q. Locate the following ground forms on the map: 
A hill, a spur, a saddle or col, a watershed, 
a water course. 

Q. You are standing at road fork 453 north of 
Longs. Draw a line from your position 
to Cumps Mill and another to the Oren- 
dorf farmhouse. Describe the country 



included in the area bounded by these 
two lines as shown by the conventional signs. 
Q. Draw the following named conventional signs 
without consulting the map. 

a. An improved road bounded on one side 
by a barb wire fence and on the other by 
a smooth wire fence. 

b. An unimproved road bounded on one 
side by a worm fence and on the other 
by a stone fence. 

c. An improved road having an embank- 
ment on one side and a fill on the other. 

d. A stream over 15 feet wide with steep banks. 

e. A stream with an improved road crossing 
it on a stone culvert. 

f. A double track railroad running through 
a cut. 

g. A woods with underbrush with an un- 
improved road running through it. 

h. A space 2 inches square with each of the 
following vegetation: corn, cultivated land, 
orchard, marsh land, cleared woods. 

i. Outline a drainage system and draw in 
the contours to show hills, cols, spurs, 
steep slope and gradual slope. 

CONTOURS 

Q. With a red crayola trace out the 440-foot con- 
tour. This is the master contour of ths 
map. From this you will be able to get the 
lay of the land. 

Q. With a blue crayola trace out the important 
streams. 

Q. With a green crayola trace out the 420 contour. 

Q. What is the vertical interval of the map? 

Q. Can you see St. Joseph's College from Four 
Points? 

Q. Can you see Emmittsburg from Longs? 

Q. Can you see Longs from Thomas Creek 
Church? 

Q. Can you see Cumps Mill from St. Joseph's 
College? 

Q. Draw a profile from road fork 481 at Long's 
to Thomas Creek Church. 

Q. Your command is bivouacked south of Longs. 
Where would you post a support of one 
platoon to observe to the north? Where 
would you locate the sentinel posts? 

Q. How would you go from Four Points to 
Cumps Mill without being observed from 
the enemy observation post at St. Joseph's 
College? 

Q. Where is the lowest point on the map? 

Q. Where is the highest point on the map? 

Q. What is the difference in elevation of the 



16 



Map Reading 



Clagett farmhouses and the cross roads at 
Fairplay? 

Q. Where is the first point south of Fairplay on the 
Fairplay-Emmittsburg road where you 
come in sight of Emmittsburg? 

Q. What is meant by the figures 462 just north- 
east of road 443? 

Q. What is the elevation of Thomas Creek 
Church; Rose Hill Farm; Cumps Mill; 
Stull; Rhodes Mill; Ovendorf farmhouse? 

Q. Where is the highest point on the road be- 
tween Emmitsburg and Fairplay? On the 
Emmitsburg-4lO-4:22-43S-road? On the 
Four Points-365-4:18-387- Matters road? 

Q. Where is the highest point in the north half 
of the Emmitsburg sheet? The south 
half? Where is the lowest point in each? 

Q. Draw a profile along a line from road fork 
488 at 342.5-735.4 to road fork 483 
at 339.7-737.9. 



VISIBILITY 

Q. You are standing at road fork 481 at Longs. 
Your eye is 5 feet 6 inches above the 
ground. The trees on hill 463 are 20 
feet high. What would be the height of 
a flag pole at road fork 418 to be visible 
to you? 

Q. You are at road fork 445 at Matters. Can 
you see St. Joseph's College? 

Q. You are at road fork 445 at Matters. Your 
eye is 5 feet 6 inches above the ground. 
How high would Martin's Mill {build- 
ing) have to be to he visible to you? 

Q. You are at Thomas Creek Church. Can 
you see Emmitsburg? Can you see 
Cump's Mill? Can you see Matters? 
Can you see the bridge over the Monocacy 
River near the Stull farm? 

MISCELLANEOUS 

Q. You have been ordered to make a sketch of 
the country bounded by lines running 
as follows: 437-402 thence to 449, thence 
to Thomas Creek Church, thence back to 
the initial point 437. 

a. Where would you locate your base line? 

b. What points would you use for inter- 
section stations and what points would 
you locate by intersection? 

Q. Your company is at the Orendorf Farm on the 
Emmitsburg Turnpike. You are ordered 
to march to Fairplay as escort for a wagon 
train heavily loaded with ammunition. 
The decision as to the road that you would 
take is left to you. What road would 
you take? 




Draw in the Contours on This Map. 



Map Reading 



17 



Q. You are at Matters. What is the direction 
of the following points: Cumps Mills; 
Four Points; Carricks Knob; the mouth 
of Toms Creek? 

MISCELLANEOUS 

Q. At what point would you disable the railroad 
between Emmitsburg and Matters? 

Q. You are commanding the advance party of 
an advance guard {one platoon) marching 
north on the 408^46-472-453 Emmits- 
burg road. The head of your platoon 
is at road fork 481. The point is on 



ahead about 150 yards. At this moment 
a signal to halt comes from the rear. A 
runner from the captain tells you that 
the halt is to be for two hours. Where 
will you post march outposts? 
Q. You are in command of a truck train of 
100 motor trucks. You are ordered to 
transport 1,500 men from Matters to 
Fairplay and then return to Matters for 
another 1,500 men. All roads on the 
map are available. Haw would you 
route your train? 



18 



Map Reading 




Draw in the Contours on This Map. 



Map Reading 



19 




20 



Map Reading 



Sketckin^ with Scale of Horizontal Equivalents^ 



The scale of Horizontal Equivalents is based 
on the fact that at a slope of plus one degree 
the ground will gain an elevation of one foot in 
every 57.3 feet. Thus, where a vertical in- 
terval of 20 feet is being used, these 20 feet 
in elevation will be gained in a distance of 20 
times 57.3, which is 1,146 feet; where the slope 
is 2 degrees the 20 feet in elevation will be 
gained in J^ of 1,146 feet, which is 573 feet; 
where the slope is 4 degrees the 20 feet in eleva- 
tion will be gained in 34 of 1,146 feet, which is 
286 feet, etc. 

From this data we are able to construct a 
scale of horizontal equivalents for any degree 
of slope by first constructing a simple reading 
scale and taking therefrom the distances as 
above indicated. 

We do not, however, have to go through all 
of this process because it has already been done 
for us. The scale of horizontal equivalents 
that is published herewith is constructed on 
the normal scale for maps prescribed by the 
Field Service Regulations as follows: 

For road maps and sketches, 3 inches = 

1 mile; vertical interval, 20 feet. 
For position and outpost maps and 
sketches, 6 inches = 1 mile; vertical 
interval, 10 feet. 

This scale is graduated from y^ degree to 
10 degrees and will be found sufficiently ac- 
curate for all practical purposes. 

Having determined the elevation of the 
initial station and plotted the distance from 
this to the next succeeding station, all you have 
to do to determine where the contours cross 
your line is to apply the scale of horizontal 
equivalents for the degree of slope determined 
and dot off the contour points. 

There is also published a scale from which 
you may secure a scale of yards with which to 
draw the sketch from the data given below: 

THE PROBLEM 

1. From the data given below draw a road 
sketch: 
General: 

Scale: 3 inches equal 1 mile. 

(Take off the 36-inch scale at the bottom of 
the illustration on page 21.) 



Vertical interval: 20 feet. 

Tupper Creek is sparsely lined with trees 
without underbrush throughout its length 
within the boundaries of the sketch. 

To the south of Tupper Creek there is a 
low, sparsely wooded ridge generally parallel 
to the creek, the top of which is about 400 
yards from the creek and approximately 100 
feet higher. 

Tupper Creek is 20 feet wide and fordable 
except in freshets. The banks are steep and 
generally from 4 to 6 feet high. All other 
creeks are less than 12 feet wide. 

A telephone line parallels the main road 
throughout its course within the limits of the 
sketch. 

The K and L. Railroad, single track, standard 
gauge, runs east and west across the sketch. 
It is generally parallel to and from 25 to 100 
yards distant from the north bank of Tupper 
Creek. A telegraph line runs parallel to the 
railroad. 

At Station 1. — Elevation 500 feet. Bearing 
along main road 85°; distance to station 2 is 
1,100 yards; slope, minus 1M°. 

Bearing right, 175°; distance to Tupper 
Creek 950 yards; slope for distance of 390 
yards is minus 2°, and for remainder of distance 
is minus 3°. 

Bearing left, 5°; distance to top of Grant 
Hill 750 yards; slope is plus 1^°. 

Bearing to mouth of Wind Run, where it 
joins Tupper Creek, is 122°; this is an inter- 
section bearing. 

Station 1 to Station 2. — Improved road, 
barb wire fence on both sides. At station 1 
plus 400 yards is the farmhouse of U. N. 
Picket on the north side of the road. A large 
bam is 100 yards to north of farmhouse. 
Grounds are 200 yards square surrounded by 
smooth wire fence. Trees here and there. 

At station 1 plus 600 yards is a barb wire 
fence, bearing 2°, which runs to the north edge 
of the sketch. Ground to east of this fence is 
in com, west of fence meadow land to Wind 
Run. All ground to south of road as far 
south as the railroad and east to Wind Run is 
in wheat. 

At Station 2. — Elevation 410 feet. Bearing 



Cut out scale of Horizontal Equivalents on cardboard sheet. 



Map Reading 



21 



along main road 110°; distance to station 3 is 
600 yards; slope, plus 4°. 

Bearing right, along Wind Run, 179°. 
This is intersection bearing to mouth of Wind 
Run; elevation at Junction of Wind Run and 
Tupper Creek is 375 feet. 

Bearing left, along Wind Run, 1°; distance 
to north edge of sketch 800 yards ; slope plus 1 H°- 

Road crosses Wind Run on King Post 
Wooden Bridge 18 feet long, 12 feet wide, and 
8 feet above water. 

Four hundred yards north of station 2 a 
small creek bearing 80° runs into Wind Run 
from the east. 



south. West slopes sparsely covered with 
woods; south and east slopes open grass 
land with trees here and there. The road 
runs through a cut for a distance of 100 yards 
on both east and west of station. 

Staiion 3 to Station 4. — Improved road, no 
fences on either side. 

At Station 4. — Elevation 400 feet. Bearing 
along main road 90°; distance to station 5 is 
1,050 yards; slope, plus H°. 

Fifty yards to south is railroad station of 
Camden. Improved road leads from main 
road to station. 

Directly south of Camden Station a small 



Length 

Pace 

30" 


of 




SCALE OF PACES 




31" 






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rr 


32" 






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33" 






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34" 








PM \V 


35" 








\M 


36" 








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3"«'lmi. ec 
6"= 1 ml. to 


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loa 200. 300 «oo 


1000 

soo 



Wind Run averages about 10 feet in width 
and is fordable throughout its length. 

Wind Run is lined with trees throughout its 
length within the limits of the sketch. 

The K. and L. Railroad crosses Wind Run 
on a stone culvert. 

Station 2 to Station 3. — Improved road, barb 
wire fence on north side, smooth wire fence on 
south side. 

From station 2 plus 200 yards to station 3 
is an orchard to the south of the road that 
extends 300 yards to the south, surrounded 
by a smooth wire fence. 

At station 2 plus 350 yards is a farmhouse 
with a bam. Home of A. B. Fox. 

Slopes of hill to north sparsely covered with 
woods. Remainder of country to south as far 
as the railroad is meadow land with trees here 
and there. 

At Station 3. — Elevation 540 feet. Bearing 
along main road 140°; distance to station 4 is 
700 yards; slope, minus 33^°. 

Bearing (intersection) to left to top of Pope 
Hill, 50°; slope, plus 4°. 

Pope Hill is a ridge running north and 



creek runs north and empties into Tupper 
Creek. 

Station 4 to Station 5. — Improved road, 
barb wire fence on each side. From Station 
4 plus 200 yards to plus 800 yards is an orchard 
extending south to the railroad. It is sur- 
rounded by a barb v/ire fence. 

At station 4 plus 600 yards to the north of 
the road is a farmhouse with a bam. Small 
grove of trees around houses. 

At Station 5. — Elevation 430 feet. Bearing 
along main road 120°; distance to station 6 at 
Chain Creek is 900 yards. Slope, minus 2°. 

Bearing right to Tupper Creek, 180°; dis- 
tance, 400 yards to creek. Tupper Creek is 
70 feet below station 5. 

Bearing left along an unimproved road 
running towards Chain Creek, 45°; distance 
to Chain Creek, 925 yards; elevation of this 
road at Chain Creek is 420 feet. Road has no 
fences. At station 5 plus 300 yards on north 
side of unimproved road is a farmhouse in a 
small grove of trees. 

Directly south of station 5 a small creek 
runs north and empties into Tupper Creek. 



22 



Map Reading 



Station 5 to Station 6. — Improved road, 
smooth wire fence on north side, rail fence 
on south side. 

Entire triangle lying between stations 5 and 
6, Chain Creek and the unimproved road 
running north east from Station 5 is in com. 

At Station 6. — Elevation 330 feet; bearing 
along main road, 90°; distance to edge of 
sketch, 600 yards. Road is level and nms 
between raihoad and Tupper Creek generally 
parallel to both. 



Bearing left along Chain Creek 358° to 
north edge of sketch; slope, plus 1J^°. 

Chain Creek is 12 feet wide and is fordable. 
Road crosses on wooden King Post bridge. 
Railroad crosses Chain Creek on stone culvert. 
Bearing to right, 45° to top of Garland Hill; 
distance, 1,000 yards; slope, plus 2°. Junc- 
tion of Chain Creek and Tupper Creek is 
80 yards directly south of station 6. 

The south and west slopes of Garland Hill 
are in grass land with trees here and there. 



Map Reading 



Map Locations by Coordinates 



The method of locating points on a map by 
means of coordinates is readily grasped if you 
foUow the few simple rules. In fact, once 
understood, it becomes almost mechanical. 

To begin with, a grid is printed on the 
map as shown on the section of the Emmits- 
burg map accompanying this text. On maps 
this grid usually consists of red or blue hori- 
zontal and vertical lines, regularly spaced 
according to the scale of the map. On the 
section of map herewith these grid Unes are 
in heavy black. For reference, they are 
always numbered left to right and from 
bottom to top, beginning at the lower left- 
hand comer of the map. On the Emmitsburg 
sheet, the lines are exactly one thousand 
yards apart. 

A point at the intersection of any two of 
these lines is designated by joining the refer- 
ence numbers of the two lines by a hyphen, 
the number on the end of the vertical Une 
being written first. Thus, the intersection of 
the two lines 339 and 728 would be written 
339-728. Now, since there is only one vertical 
line ending in 39 and one horizontal line 
ending in 28, there can be no confusion if the 
first figiire of each numeral is omitted, thus 
(3)39-(7)28, or 39-28, or still more simply 
3928. 

Reversing the operation, suppose that it is 
desired to find the intersection that has been 
designated as 3929. Only one of the vertical 
lines ends in 39, namely, 339; only one of the 
horizontal lines ends in 29, namely, 729. The 
desired intersection is therefore where these 
two lines cross — just east of Lime Kiln. 

It is, of course, necessary to designate points 
which do not fall at the intersections of the 
grid lines. For this purpose, fractional parts 
of the distance between the grid lines are used. 
These fractional parts are always measured 
from the lower left-hand comer of the square 
in which the point is located. For example: 
assume that it is desired to designate a point in 
the exact middle of one of the squares. Such 
a point is halfway between two of the vertical 
lines and halfway between two of horizon- 
tal lines. Let us take the point A. It is half- 
way between the vertical lines 338 and 339, 
hence is 3383^, or written decimally, 338.5; 
similarly, it is halfway between 727 and 728, 



and is written 727.5. Expressed as explained 
above, the coordinates of the point A would 
be written 338.5-727.5, or omitting the first 
figure of each numeral and the hyphen, 385275. 

To illustrate how any other point in a square 
may be located, let us take the house in the 
square bounded by the vertical lines 339 and 
340 and the horizontal lines 726 and 727. 
To find the coordinates, first draw the dotted 
line ab parallel to 726, then draw a second 
dotted line ac parallel to 339. Now, using the 
scale at the bottom of the map and measuring 
the distance from the intersection of the two 
lines to c, we find it to be four-tenths. It is 
therefore written 339.4. Similarly, measimng 
to b, we find it to be six-tenths. It is written 
726.6, and the coordinates of the point are 
339.4-726.6, or 394-266. 

To avoid the necessity of drawing lines on 
the map and to facilitate measuring, use is 
made of a scale such as shown in Fig. 1, 
cut from stiff paper or celluloid. Each leg of 
the scale is the same length as the side of one 
of the squares, and each is divided into ten 
equal parts. These divisions, representing 
in this case one himdred yards, are numbered 
from the intersection of the legs outward as 
shown in the figure. 

Using the scale to find the coordinates of 
any point, such as the house in the square 
bounded by the vertical lines 339 and 340 
and the horizontal Unes 728 and 729, place 
the scale on the map as shown, one leg parallel 
to and along the horizontal line 728. Slide 
it along the horizontal line until the vertical 
leg passes through the house. Now read the 
horizontal leg. In this case it is 339.6. Write 
it down as described, 396. Now read the 
vertical leg. It is 728.5. Written as de- 
scribed it is 285. The complete coordinates 
of the house are therefore 396285. 

To reverse the operation, let us locate on 
the map a point whose coordinates are written 
393295. Looking at the first, second, fourth 
and fifth figures, we see that the point must be 
in the square whose lower left-hand comer is 
at the intersection of the lines 339 and 729. 
Placing the zero of the scale at this intersection 
and sliding the scale along the line 729 until 
the reading 3 is at the intersection, then reading 
up the vertical leg until we come to the reading 



1 Cut out coordinate reading scale on cardboard sheet. 



24 



Map Reading 




Reducedfroml2inWarGameMap, '° gg^ 

By the Engineer Depi;,Arnriy Service Sehools, 
Fbr+ Le avenwor+h, Kas. 



50Q 



Map Reading 



25 



5, we locate the desired point at the road 
fork 478. 

The system of coordinates we have just 
described is sometimes designated as six- 
figiire coordinates. In using this method of 
designating coordinates, the French discard 
the first two figures of each numeral, retaining 
only the last figure of each numeral and the 
decimal. Thus, under the French system, 
the coordinates of the road fork at 478 would 
be 339.3-729.5. Eliminating the first two 
figures of each numeral, we have 9.3-9.5, or 
leaving out the hyphen and decimal points, 
9395. 

This can be done without danger of confusion 
provided the final figure in the reference 
numbers of the vertical and horizontal lines 
does not appear more than once on the map. 
This means that the nvmiber of grid lines 
must not exceed ten each way. If there is a 
greater number, there will be confusion. For 
this reason, it is safer to make use of the six- 
figure coordinates. 

Problems^ 

Map: Emmitsburg Sheet 

Q. Give the coordinates for the following points: 
The crossroads at Fairplay; road fork 
437, east of Thomas Creek Church; 
Cumps Mill; Rose Hill farm. 

Q. A message gives the location of the front 
lines as follows: 345.2-730.7; 345.2- 
732.4; 345.6-732.4; 345.7-733.5; 345.3- 
733.6; 344.9-734,4. Locate the line 
on the map. 

Q. A message gives the location of an enemy's 
battery at 342.2-735.4. Locate it on 
the map. 



Q. Locate the 383-420-Thomas Creek Church- 
Martins Mill-Four Points-365-405-468- 
453 road by means of coordinates. 

Q. Your patrol advanced by the following 
route: 340.2-730.9; 341.0-731.5; 342.3- 
731.5; 342.9-731.2; 353.1-732.4; 343.5- 
732.4; 344.5-732.5; 345.3-733.2. Locate 
the route on the map. 

Q. Messages have been received at Army Head- 
quarters giving the following points on 
the enemy's line. Indicate on the 
map where you estimate it to be: 343.5- 
729.1; 343.2-729.6; 342.7-730.1; 342.6- 
730.6; 342.9-731.1; 343.1-732.5; 342.4- 
733.5; 341.3-734.5. 

Q. An aviator reports an enemy battery going 
into position at 341.2-730.5. You are 
at 343.2-731.7 with your machine gun 
platoon. What would you do? 

Q. You have a platoon of machine guns con- 
cealed in the edge of the woods at 345.4- 
735.4. An enemy infantry column is 
reported marching north on the 346.0- 
732.7 - 346.2 - 733.4 - 346.1-735.3 road. 
The head of the support of the advance 
guard is at 346.3-734.7. You decide 
to open fire. What range will you give 
your gunners? 

Q. The line of resistance of your outpost extends 
along the line A'i9-Thomas Creek Church- 
420. How would you define this line 
in a message, using the system of co- 
ordinates? 

Q. Locate the following points by coordinates: 
The bridge over the Monocacy northwest 
of Stull farm; Rhodes Mill; St. Mary's 
College; Clagett farmhouse; Cose farm- 
house. 



1 Cut out coordinate reading scale on cardboard sheet. 



26 



INIap Reading 



SCALES 

1. The distance from A to the center of the bridge 

at E is 1,800 yards. Construct a scale 
of yards for the map. What is the R. F.? 

2. How long would a force marching at the rate of 

88 yards per minute take to march from 
T to the bridge at E via G and H? R. F. 
of map is 1:21120. 

3. // the scale of the map is 6 inches to one mile, 

•what is the range in meters from A to B; 
A to C; M to J? 

4. The head of an infantry column crosses the 

bridge at E at 9.05 a. m. What time will 
it reach F? Scale of map 1:10000. 

5. A cyclist traveling at the rate of 12 miles per 

hour takes 3}/^ minutes to go from R to S. 
Construct a scale for the map to read 
quarter miles. 

6. Sound travels at the rate of 1,100 feet per 

second. How soon afterwards will the 
report of a rifle fired at A be heard at D 
and N respectively. R. F. of map is 
1:20000. 

7. An aviator traveling in a straight course from 

M to K at the rate of 60 miles per hour 
passes over M at 7.35 a. m. What time 
will he pass over K? R. F. 1: 50000. 

8. The scale of the map is 6 inches to 1 mile. 

You have a machine-gun platoon at A. 
What range would you give your gunners 
to the cross roads at H? 

CONTOURS 



\. If X is at an elevation of 520 feet and A is 
570 feet, what is the vertical interval? 

2. If the contour at B is 220 feet, give the heights 

of contours cut by a line drawn from D 
to N. The V.I. is 20 feet. 

3. What is the height of D, J, and A, if the 

height of R is 100 feet and the vertical 
interval is 20 feet? 

4. Examine the road E-H-G-T. Where is the 

gentlest and steepest slope? 

5. Indicate the numbering of the contours on a 

line down from E to G. Height of M 
is 240 feet. The V. I. is 20 feet. 

6. Assume the heights of A and B to be 520 feet 

and 480 feet respectively. What would 
be the heights of J. D, N and E? 

7. An aviator flies 1,800 feet above B and 

travels in a straight line across the map. 
At what height will he pass over the bridge 
at E which is 10 feet below the adjacent 
contour? The V. I. is 40 feet. 



Problems 

Map — See Page 27 

8. State whether the following slopes are con- 
cave or convex: A to H; A to E; H to C; 
U to H; D to V. 

9. Can a man standing at A see others at H; E; 
C; K; B; T? 

10. Are the following points visible from W: 
U, R, B, N? 

11. Is E visible from H; D from G; B from A; 
U from R; V from X; N from S; D from 
H? 

12. Show where a line of light from M through 
W would strike the ground. 

13. A scout from the north reaches the point N. 
Will he be able to see the bridge E; bridge 
H; a house 15 feet high at B; a Wall 10 
feet high at T; a signalman at Q? 

14. What must be the heiglit of a post at P to be 
visible from C? 

15. At what point would you establish a signal 
station to communicate with H, X, E, K 
and G? 

16. At what points would signal stations have to 
be established to communicate between B 
and E by visual signaling? 

17. Draw a profile on the line X-N. Is X 
visible from N? 

18. Suppose the bridge at H to be 10 feet below 
the nearest contour. When will a man 
come into sight, who is descending to the 
river by the trail from M, to a scout 
standing in the middle of the bridge? 

19. When an aeroplane was over S a tree at Y 
was just visible acoss the hill A. At 
what height was the machine flying 
above S? 

20. Two patrols are advancing from E, No. 1 
via the E-K-G road and the other via the 
E-H road. When will each come under 
the observation of a scout located at U? 

21. Make a section along the line M-K; M-B; 
E-B; and M-N. 



CONVENTIONAL SIGNS 



1. A 



single track railroad enters the map at the 
southwest corner and runs via U, G, and 
K to the north edge of the map. Draw it 
in, showing the necessary cuts and fills to 
keep it level throughout its length. V. I. 
is 10 feet. 
2. Fill in the following with conventional signs: 

(a) The village of Kent is at H. 

(b) The ground in the river bottom on the 
south side of the river south of X is 
marshy. 



Map Reading 



27 




28 



Map Reading 



(c) The underfeature W is wooded. 

(d) The ground in the river bottom west of 
V on the west bank is marshy. 

(e) The road between Q and S runs 
through a cut. 

if) There are trees along the river through- 
out its entire length, 
(g) The triangle K-G- Y is under cultiva- 
tion. 

(h) Between and T and extending half 
way to the river is a large orchard sur- 
rounded by a barbed wire fence. 



(i) There are farmhouses and barns at 
the following points: R, Y and T. 
(j) A telephone line parallels the road 
F-H-E. 

(k) The quadrangle E-K-G-H is cut up 
into fields by wire fences, and is cultivated. 
There are trees sparsely scattered through- 
out the area. 

(/) The country east of the H-E road as 
far as the river is in meadow land with 
a few trees here and there, 
(m) The hill between B and U is heavily 
wooded. 



Infantry 

Drill 

Regulations 

(Provisional) 

1919 

Illustrated and 
annotated 

Price 75 cents 



The 
Corner 
Stones 

of a 
Military 
Library 



Military 
Signaling 

A complete manual 
of visual signaling. 

Will keep you off the 
Signal black list. 



Price 60 cents 



Every Soldier in the Service should have a 
small library of Military books of his own. 
Here are four books that we recommend. 



Infantry 

Score 

Book 

The Soldier's manual 
of individual marks- 
manship. Fully illus- 
trated. Ample supply 
of Score Sheets for your 
target practice. 

Price 35 cents 



The 

United 

States 

Infantry 

Association 

Union Trust 
Building 

Washington 
D. C. 



Scouting and 

Patrolling 

Tells you in language 
you can understand all 
about what to do as a 
scout and how to con- 
duct the operations of 
a patrol. The best Sol- 
dier books in print. 



Price 75 cents 



A Few Good Books 

Specially Selected from the Shelves of the Infantry- 
Association 

Thirty-Minute Talks — Stewart-Waldron $2.50 

A collection of twenty every-day talks on military subjects in language that 
the man new to the service can understand. These talks will serv^e to keep 
you in touch with the "Military Game" — they will save you a lot of time 
"brushing up" when called upon for a talk on a military subject. 

Company Administration $2.50 

Based on special regulations No. 57, War Department. To the original text 
there have been added all of the blank forms, properly made out in detail, that 
pertain to the administration of the company, troop and battery. You can't 
go wrong on paper work if you follow Company Administration. 

Scouting and Patrolling — ^Waldron .75 

A little book that tells in language the soldier can understand, how a scout 
goes about his work as an individual and how the operations of a patrol are 
conducted. Endorsed by leading officers of the Army. Revised and brought 
up to date to include the experiences of the World War. Fits the pocket. 
Illustrated. 

Army Physical Training — ^Waldron $1.50 

The system of setting-up exercises in the Army fully explained and illustrated. 
Detailed instruction for every movement — what to do and what not to do. 
Exercises classified in series and commands for each worked out in detail. 

American Rifle — Whelen $5.00 

The manual of the rifle — military and sporting — prepared by America's 
foremost expert on rifle firing. Handsomely bound and fully illustrated. 

Tactical Walks — Waldron $1.50 

The book that sets forth in detail the up-to-date method of training in infantry 
minor tactics. Model problems prepared that may be fitted to any terrain 
that may be available. The discussions, explanations and solutions bring 
out the principles of minor tactics. Will save many hours of preparation in 
the conduct of tactical walks. 

Military Signaling .60 

A complete pocket manual of military signaling. Arm signals prescribed in 
par. 43, 1. D. R., explained and fully illustrated. Semaphore code illustrated 
by new drawings. Wig-wag code. Heliograph and projector signaling. 
Instructions for the establishment and maintenance of signal stations. Use 
of cipher codes. Detailed instruction for military message writing. Paper 
bound. 

Platoon Training — Waldron Per Set, $2.50 

A complete infantry training manual. Covers all the subjects that a platoon 
commander must know about. -The book that you need every day. Pub- 
lished in two handy volumes. Volume I contains the infantry drill regu- 
lations and all discipHnary and general subjects. Volimie II contains chapters 
on the weapons with which the infantry soldier is armed . Profusely illustrated . 



A Few Good Books 

{Continued) 

Infantry Score Book — Whelen .35 

The "dope" that the individual requires for his individual instruction in rifle 
practice, prepared by America's foremost military rifleman. An ample 
supply of score sheets for the season's target practice. The best score book 
that has been produced. Completely illustrated with excellent Hne drawings. 

Military Sketching and Map Reading — Grieves $1.50 

A complete text-book that contains all that you need to know about the 
subjects. Specially suited for beginners. Recognized throughout the sendee 
as the standard for N. C. O. unit schools, R. O. T. C. units, reserve officers and 
National Guard. 

Tactics and Technique of River Crossings — Kreuger $2.50 

The only text-book that has been published covering this important subject. 

Mass Physical Training — Raycroft $5.00 

Approved by the War Plans Division General Staff. "Contents forms the 
basis for the training and instruction of the military service of the United 
States in Physical Training." Extract from foreword by Major General 
Haan, chief of War Plans Division. Profusely illustrated. Chapters on the 
tactics of baseball, football, and basket ball that are the best that have ever 
been produced. 

Defense of Duffers Drift — Swinton .50 

An interesting story of the Boer War that brings out and illustrates the prin- 
ciples of minor tactics in a most attractive and impressive manner. 

Infantry Drill Regulations (Provisional) 1919 .75 

U. S. Infantry Association Edition, Annotated and Illustrated. Bound in 
good cloth. Fits the pocket. The one book that every officer and soldier 
must have. 

Elements of Military Hygiene — Ashburn $2.50 

The recognized American text-book on the subject. 



ORDER BLANK 



□ American Rifle 

□ Army Physical Traiung 

□ Company Administration 

□ Defense of Duffer's Drift 

□ Elements of Military Hygiene 
n Infantry Drill Regulations 

(Provisional) 1919 



□ Infantry Score Book 

□ Mass Physical Training 

Q Military Sketching and Map 
Reading 

□ Military Signaling 

□ Platoon Training 

Q Scouting and Patrolling 



□ Tactical Walks 

Q Tactics and Technique of River 

Crossings 
Q Thirty-Minute Talks 



.1920 



The U. S. INFANTRY ASSOCIATION, 

Union Trust Building, Washington, D. C. 

Inclosed please find for 

Please forward to the address below the books checked on this blank. 



Dollars 



Address, 



WRITE ADDRESS 
PLAINLY 



Thirty-Minute 
Talks 

By 

MAJOR M. B. STEWART 

and 

MAJOR W. H. WALDRON 

Cloth Bound— 387 Pages 

Explaining is half the work of instructing. Talk saves work — when it 
is the right kind of talk. For the instructor, explaining — talking is the 
hardest part because it means constant brushing up, reading, study, thought 
and plannmg — all of which takes time, and time counts heavily in the game 
of intensive training. 

THIRTY-MINUTE TALKS are offered as time-savers for the in- 
structor. They are in no sense treatises of the subjects considered — ^just 
plain, everyday talks, in language the man new to the service will be able to 
understand. They will save the instructor's time by furnishmg hun with a 
guide which he may rearrange or elaborate as he chooses. 

The subject-matter of the Thirty-Minute Talks is as follows; 



Organization. 

Training. 

Instructing. 

Physical Development. 

Close Order Drill. 

Extended Order Drill. 

Military Courtesy. 

Military Discipline. 

Care of Arms and Equipment, 

Advance Guards. 



Outposts. 

Scouting and Patrolling. 
Combat. 

Approach March and Deploy- 
ment. 
Musketry. 

Orders and Messages. 
Field Fortifications. 
Map Reading. 
Military Sketching. 
Contouring. 



PRICE $2.50 POSTPAID 



The United States Infantry Association 

Union Trust Building, Washington, D. C. 



LIBRftRY OF CONGRESS 



011 523 001 3 



